Antenna



FIG. 1 is a top plan view of an antenna on a base in broken lines;

FIG. 2 is a side elevation view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a top perspective view thereof;

FIG. 6 is a top plan view of an antenna without environment; and,

FIG. 7 is a rear elevation view thereof.

The broken lines illustrate the environment of the antenna and form no part of the claimed design. 

CLAIM The ornamental design for an antenna, as shown and described. 